The disclosed embodiments relate to a medical device comprising an incising member for incising a stenosis or stricture in a blood vessel or in a digestive organ in a longitudinal direction of the blood vessel or digestive organ.
Conventionally, a stenosis or stricture formed in a blood vessel or in a digestive organ is treated by a well-known method, in which the stenosis or stricture is dilated with a medical device such as a balloon catheter. Such a medical device generally has an expandable-and-contractible member capable of radially expanding and radially contracting (a balloon or a mesh member, for example), and the expandable-and-contractible member radially expands to dilate the stenosis or stricture.
When the stenosis or stricture is highly calcified, however, it is difficult to dilate it with the expandable-and-contractible member alone. So, in this situation, a known medical device (an incising device) is used that has an incising member disposed in the longitudinal direction of the medical device. To operate the medical device, a balloon catheter is inserted into the interior of the incising member and then the balloon is expanded so as to radially expand the incising member (see U.S. Patent Application Publication No. 2013/0041391 discussed below, for example).
In the medical device of U.S. Patent Application Publication No. 2013/0041391, the incising member (a cutting element), which is disposed in the longitudinal direction, is directly fixed to an outer circumference of the expandable-and-contractible member (an expandable scaffold). That is, the incising member is directly fixed to a wire that constitutes the expandable-and-contractible member. Upon radial expansion, the expandable-and-contractible member can incise a stenosis or stricture in the longitudinal direction.
Generally, as the expandable-and-contractible member expands radially, it contracts in the longitudinal direction (in other words, as the expandable-and-contractible member expands, it becomes shorter). In the medical device described above, the incising member is directly fixed to the outer circumference of the expandable-and-contractible member via the wire that constitutes the expandable-and-contractible member and therefore cannot move in the longitudinal direction as the expandable-and-contractible member expands or contracts. Consequently, upon attempted radial expansion of the balloon of the balloon catheter inserted in the interior of the expandable-and-contractible member, the radial expansion of the expandable-and-contractible member is interfered with by the incising member, which is a problem. In addition, when the expandable-and-contractible member is forced to expand, the incising member comes off the expandable-and-contractible member, which is another problem.
Sometimes, upon expansion of the expandable-and-contractible member, the stenosis or stricture can be partially caught between the expandable-and-contractible member and the incising member. When the handler manipulates the medical device in the longitudinal direction, the stenosis or stricture thus caught can cause the incising member to come off the expandable-and-contractible member, which is another problem.